Hollow core panels and a method for constructing the same



'March 3, 1959 .1 D EVES 2,876,053

HOLLOW CORE PANELS AND A METHOD FOR CONSTRUCTING THE SAME Filed Nov. 6, 1956 2 Sheets-Sheet 1- INVENTOR JZ /M 17. Eves I BY ATTORNEYS .Filed Nov s, 1956:

March 3, 1959 J. D. EVES 2,876,053

v HOLLOW CORE PANELS AND A METHOD FOR CONSTRUCTING THE SAME v v Z Sheets-Sheet 2 MHW I INVENTOR 10/114 17. Eva;

' ATTORNEYS United States Patent HOLLOW CORE PANELS AND AMETHOD FOR CONSTRUCTING THE SANIE Application November 6,1956, Serial No. 620,738 4 Claims. o1. 311-106,)

This invention relates to lightweight panels and the method for making the same. More specifically it relates to hollow core panels 'havin'g means integral therewith for connection to a support structure. I

For many years hollow core panels, of one .form or another, have been in use, their particular utility being in building construction, furniture making, boat building or other fields of endeavor where strength and lightness of material are required. Panels of this type generally comprise two sheets of a material such as plywood, :hardboard or the like in spaced parallel relationship with a reenforcing cellular type structure firmly secured between the sheets. The utility of this type of panel has been proven over the years and the economic advantages received as a result of their use have made them an .important factor in our modern scientific economy.

Problems have arisen, as a result of .the general .ac-

ceptance and diversified fields of use'in whichhollowcore panels are'ernployed. These pertain tomeans for secure ingthe panels in place. The conventional securing means, such as nails, screws and bolts, are not generally adaptable for hollow core panel use, since insuflicient .bodyis .provided by the panel to retain the securing means under pressure. To overcome this problem, blocks have been inserted. between the sheets, within the hollow core .of the panel. These blocks provide the required body, but in themselves give rise to certain other problems.

In order fora 'blocktofunctiomas required,,it must completely span the space between the sheets forming the outersurfaces of the panel. Such a requirement calls for exact dimensioning. v A'block whichlis too small will fail toprovide'the proper support for securing means, and if the securing means are tightened enoughto obtain support, the surface sheets will be deformed as they are drawn in toward 'the -blo'ck. A block which is too large will force portions ofthe sheets outwardly, resulting in uneven surfaces. In order to provide blocks of proper dimension, time and skill are required reducing the economy of the panels and diminishing their value.

A further objection, 'to the use of blocks in panels to support securing means, should here be pointed out. The use of too many blocks within a panel will reduce the hollow core area and thus'add 'tothe weight of thepanel.

This invention is directed to the elimination of the difficulties, set forth above, in'the manufacture and utilization of hollow core panels.

The principal object of the invention is to provide a panel which may be secured to a support or other structure; 7

Another object of the invention'is to'prov'ide a secur ing element for permanent association with a hollow core panel, whereby'thepanel may be attached to a support structure;

An additional object of the invention "is to provide a securing plate, for permanent association with a hollow core panel, which'is associable with-varied types'of securing'means, whereby thepanelmaybe attachedto a support structure.

2,876,053 Patented Mar. 3, 1959 ice It is also an object of the invention to provide a structure which is economical to manufacture and of such ug ed de ign a owithstand rough reatm n Itis further an object of this invention to provide a method formanufacturing the same. i V

It is contemplated that the invention will comprise upper and lower sheets in spaced parallel relation with a cellular type core filling the area therebetween .and a securing plate adjacent the lower sheet and imbeddedin the .core material, such that forces exertedagainst the plate will be distributed .to the upper sheet through the core.

With these and other objects in mind, reference is had to the attached sheet of drawings, illustrating t e invention, as employed in a table top, wherein like characters represent like parts, nd in which:

. Fig. 1 is an exploded fragmentary perspective of atable including a hollow core panel table-top;

Fig. 2 is a fragmentary section of the securing means o f;Fig. 1; i

' Fig.3 is a plan view of'one formof securing means;

Fig. 4 is an elevated View of the securing means of Fig. 3; e

Fig. 5 is a fragmentary cross-section illustrating a securing plate imbedded in hollow core material; 7

Fig. 6 is .a bottom plan view showing securing plates as part of a hollow .core panel blank;

Fig.7 is a top plan view of a securing plate; and

Fig. 8 is a section taken in the direction of the arrows 88 in.Fi g. 7.

As above set forth, hollow core panels may be em ployed in many varied ,fields of endeavor. With this in mind, and in order to more clearly explain the invention, the panel and ,one form of securing ,means ,are illustrated as part of .allightweight table. v

The embodiment of the invention, in a table, as hereinafter set forth was purposely chosen due to the important advances the inverition provides ,in the table making art. In this field strength and lightness are not the only characteristics sought after; beauty and simplicity of ,design and structure are not unimportant factors.

This invention provides fhollow core panels for table tops W'h'ich not fonly' fulfill the strength and lightweight requirements, but provide, at a minimum of time and expense, relatively smooth and unmarred surfaces. The invention further provides a simple and inexpensive securing means, integral with the panel, for connecting the panel to a supporting leg structure.

In Fig. '1 a portion of a table is shown in exploded perspective. The table comprises, basically, a hollow corepanel table-top and a supp'ortingleg structure which is generally indicated at 1'0.

The leg structure maybe of many types, including collapsible and non-collapsible, as long as means are provided for attaching the support to a table-top. The leg structure illustrated forms no part of the invention and has only been used to facilitate and simplify the explanation. The support structure shown is of the non-collapsible metal frame type. Rigid'elongated strips 11 and 12 are provided. The center portion of strip 11 is bulged downwardly, as at 13, to accommodate strip 12 such that on crossing the strips they lie substantially in the same plane. Brackets 14 connect the ends of strips 11 and '12. The strips and brackets may be permanently connected by any means 'known to the art or may be assembled pieceby piece into a finished table. The end portionsl'S of'brackets14 arebent downwardlyat right angles to the brackets to form .receiving arms for legs 16 andbrace "17. The'legs andbrace maybe connected by welding or any other means common to the art. Openings 1'8 are pr ovided in legs '16 andjarms 15, whereby the legs may be retainedbetween'the arms by bolts (not shown). Openings 19 are provided in brace 17, bracket 14 and strips 11 and 12 to receive a securing means forming part of the hollow core panel table-top.

The hollow core panel table-top comprises a lower sheet portion 20 having openings"21 to be aligned with openings 19 in the support structure when the table is assembled. Securing means, generally indicatedat 22, comprise a plate 23 having an opening with a bolt 24 welded therein. The securing means are positioned such that the plates 23 are in surface to surface contact with sheet 20 and the bolts 24 extend through the openings 21. It should at this point bementioned that the securing means may take many forms, depending on their location within the hollow core panel. Figs. 3 and 4 illustrate one basic type of securing'means in which the bolt 24 is connected to the plate 23 at its center. The securing means in Fig. 1, indicated at 25, shows the bolt connected, in an off-center position, to the plate. plates 23 may, of course, be provided with a female means for receiving a bolt'or with any form of securing element known to the art. Such variations in design may be necessitated by the remaining structure of the panel, to be hereinafter described.

The

A frame 26 of wood, or any other suitable material,

is fastened to sheet 20 adjacent the edges thereof such that an enclosure is defined. As can be seen in Fig. 2, the securing means lie wholly within the area enclosed by frame 26. A cellular type reenforcing structure 27 is positioned in the enclosure defined by the frame, substantially filling such enclosure and retaining the plates 23. of the securing means 22 in position with respect to sheet 20. An upper sheet portion 28 is fastened to frame 26,such that a panel is formed wherein the sheets 28 and 20 and frame 26 provide a completely enclosed area housing cellular structure 27 and securing means 22.

The hollow core table-top panel, as above described, is removably connected to the supporting structure 10 through the securing means 22. The bolts 24, which extend through openings 21, are aligned with and passed through openings 19 in support 10. The bolts 24 are retained in such position by means of nuts or other lock ing devices (not shown). It can be readily seen that the strips 11 and 12 and the brackets 14 may also be retained in position with respect to each other by means of bolt 24 of securing means 22. In' this manner, and in the absence'of welds or other permanent connections, a table is provided which may be completely disassembled for storage. It should here be' pointedout thatfthe bolts 24 secure legs 16 against all movement with respect to bracket14 and arms 15 by extending through openings 19 in brace 17.

It is of course obvious, that the hollow core tabletop and securing means heretofore described may take many difierent form's. Sheet metal screws, blind rivets and many other types of securing elements may be substituted for the bolt 24 of securing means 22. The plates 23 may be located at any point on the inner surface of sheet 20 and may be utilized singly, in clusters or spaced throughout the area defined by frame 26.

The hollow core panel as above described is readily adaptable to modern production methods. The lower sheet 20 is provided on one surface thereof with a coating of glue or other adhesive material. 22 are positioned on the sheet 20 with the bolts 24 extending through the openings 21. At this time additional adhesive'may be provided on the upper face of plate 23. The frame 26 is positioned on sheet 20 defining an enclosure and cellular structure 27 is positioned within such enclosure over securing means 22, such that the enclosure is substantially filled thereby. Finally an upper sheet portion 28, coated on one surface with adhesive material, is positioned in covering relation to said enclosure and frame and the panel is pressed such that the parts are retained in fixed position by the adhesive material. If the panel is to be utilized as a table-top 4 a trim or molding, not shown in the drawings, may be afiixed to the edges thereof or the sheets- 20 and 28 and frame 26 may be of such character as to provide the desired decorative finish.

It should here be pointed out that the securing means 22 are pressed into the cellular structure 27 adjacent the lower sheet 20. To facilitate this, glue or other material are provided on the upper face of plate 23, to soften the cellular material in the area contacting that plate, such that the plate might be imbedded or nested in such material. With the securing means positioned, as it is, between the cellular structure and the lower sheet, there is no possibility of upper sheet 28 being distorted by the securing means. All forces or pressures exerted through the securing means, from the support structure, will be distributed over a relatively greater area of the upper sheet than would be the case if direct contact ulllere made between the securing means and the upper s eet.

In some instances a securing plate of greater thickness, than that which may readily be pressed into the core material, is required. Figs. 7 and 8 illustrate a securing plate having a dished out configuration, which facilitates the nesting of the plate within the core material. The plate comprises a substantially fiat rectangularbody 35 having gently upturned sides 36 which are sharpened at 37. In use the plate is positioned on the lower sheet with its sharpened edges 37 directed upwardly and away from that sheet. When the core material is positioned within the frame of the panel the sharp edges 37 cut their way into that material enabling the plate to become imbedded therein.

It is contemplated that hollow core panel blanks may be desired, which are adaptable for use with securing elements other than bolts 24 and which, further, may be associated with varying types of supports by merely utilrzrng an appropriately located securing plate. Figs. 5

. and 6 illustrate one form of such hollow core panel The securing means blank. The blank comprises a lower sheet 29 of hardboard or other material. Securing plates 30, preferably of metal, are positioned in any desired pattern on the upper surface of sheet 29, such that securing elements may be connected to any one or a combination of plates for attaching the panel to a support structure. In Fig. 6, ten plates have been shown positioned in parallel columns and spaced from the edges of sheet 29. A frame 31, which is positioned and secured on sheet 29, defines an enclosure wherein a cellular core material 32 isseated. The core material 32 substantially fills the enclosure and provides a nest for the plate 30. An upper sheet 33 is secured in covering relation to frame 31 and core material 32, thus closing the area defined by the frame. The panel edge, defined by sheets 29 and 33 and frame 31 may be curved as at 34 to provide a decorative finish. 7 Of course, any other means known to the art may be resorted to.

As shown in Fig. 6, a panel blank is provided wherein the securing plates are fixed within the panel body. In order to utilize a desired plate it is necessary to provide an opening in the sheet 29 and connect a securing element to the plate. As aforementioned, these elements may take many forms, including rivets, female threaded plugs, bolts and sheet metal screws, etc. To facilitate locating the desired plates, within the panels, codes, such as color markings may be applied to the underside of sheet 29.

Thus, among others, the several objects of the invention as aforenoted are achieved. Obviously numerous changes in construction and rearrangement of the parts might be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

1. A hollow core panel for connection to a supporting structure comprising a lower sheet portion having an inner face, an upper sheet portion parallel to and spaced from said first-named portion, a frame connected between said sheet portions defining an enclosure, a cellular structure substantially filling such enclosure for reinforcing and spacing said sheet portions and a securing plate engaging the inner face of the lower sheet portion in substantial face-to-face contact and being embedded in said cellular structure, wherebyon a force being exerted against said securing plate-the resultant stress will be distributed to said upper sheet through said cellular means.

2. A hollow core panel as in claim 1, wherein said lower sheet portion is formed with bolt receiving openings and said securing plate is formed with a bolt rigidly connected normal thereto, said bolt being aligned with said bolt-receiving opening and extending therethrough.

3. A hollow core panel as in claim 1, wherein said securing plate is formed with a gently upturned periphery provided with sharp edges such that the plate is readily embedded in said cellular means.

4. A method for constructing hollow core panels adapted to be secured to a support structure comprising: providing a lower sheet portion applying adhesive material on substantially the ntire area of one face of said sheet portion, positioning a frame on said one face of said sheet portion such that an enclosure is provided with said adhesive interposed between said frame and said sheet portion, positioning a securing plate on the inner face of said sheet within said enclosure, applying adhesive material to the exposed surfaces of said securing plate directed away from said lower sheet, applying cellular reinforcing means to substantially fill said enclosure and be in contact with the exposed adhesive material therein and nest said securing plate by softening said cellular means adjacent said securing plate by the exposed adhesive material thereon, positioning an upper sheet portion having an adhesive coated underside in covering relation to said frame and cellular means and applying pressure to the sheet portions such that a unitary structure is provided.

References Cited in the file of this patent UNITED STATES PATENTS 435,337 Wessenius Aug. 26, 1890 770,587 Kling Sept. 20, 1904 1,779,426 Frederick Oct. 26, 1930 1,876,330 Loetscher Sept. 6, 1932 2,269,331 Arbron Jan. 6, 1942 2,305,870 Haberstump Dec. 22, 1942 2,477,852 Bacon Aug. 2, 1949 2,479,342 Gibbons et al. Aug. 16, 1949 2,489,118 Brinker et al. Nov. 22, 1949 2,609,068 Pajak Sept. 2, 1952 2,646,327 Saaf July 21, 1953 2,772,936 Bargen Dec. 4, 1956 

